Cable connecting devices are generally well known but the devices of the prior art do not provide suitable means for securing and pulling delicate fibre optic cable. The closest example of the prior art may be found in my earlier pulling eye assembly, the subject of U.S. Pat. No. 3,989,400 which issued July 30, 1976. That Patent describes a pulling eye assembly which is attached to a terminal end of a communication cable and the assembly uses an elongated metal sleeve which receives the communication cable and is crimped around it. The assembly includes a central block member with a barbed spigot coaxially positioned in the tubular end, this spigot being driven down into the center of the communication cable and the outer sleeve is then crimped around the cable intermediate the barbs.
The purpose of the present invention is to provide an advanced system for pulling fibre optic cable in telephone trunking, long haul transmission and the like. The present invention provides improvements over my earlier U.S. Pat. No. 3,989,400 and the purpose of the present invention is to provide a pulling means which on the one hand will not damage the delicate fiberglas strands which are positioned in the plastic sheathed fibre optic cable while on the other hand providing means that will give a load potential of the pulling eye that exceeds the tensile strength of the steel strength members positioned centrally in the fibre optic cable. The pulling device is designed to pull directly on the center strength steel or fibre member without destroying or breaking the fiberglas strands and holding a pressure seal at the same time. Tests of the present invention have shown that the locking of the pulling device onto the strength member of the fibre optic cable exceeds the steel breaking strength thereof. This allows the pulling of much longer lengths of cable than that attempted by other known means or methods.
There are of course fewer splices required when the present invention is used and field costs for pulling and splicing cable are therefore substantially reduced. It follows also that the number of planned field engineered splices and manholes in underground systems can eventually be reduced.
The pulling eye of the present invention can be easily installed by a workman in the field or installed at a cable factory. Fibre optic cable offers major advantages over coaxial cable such as imperviousness to interference, lower weight, smaller dimensions and fewer intermediate regenerators for equal transmission capacity.
The pulling device is designed to be adapted to the terminal end of fibre optic communication cable and includes an elongated metal sleeve or plastic sleeve open at one end to receive the cable. The steel or plastic sleeve is welded or otherwise secured to the head portion of the pulling device or it can also be sealed by a shrink method using a plastic or fibre material.